Scientists baffled by grey whale sighted off Israel : "Every spring, grey whales head north to the icy Arctic Ocean to feed. But the ice there has been melting at an alarming rate. So the theory is that after the whale left its mating grounds near Mexico, it travelled to the North Pacific, then travelled though the now open Northwest Passage and found itself in the Atlantic.
From there, it must have kept going, turning left when it reached Gibraltar, into the Mediterranean, before finding itself off the shores of Israel.
'If it did in fact go through the Arctic, it would be one of a number of species that are recolonizing the Arctic where they've never been known before in human memory,' says Barrett-Lennard."